LWIR By Tracy Rose Aquiline Photography of Colorado Springs, Colorado
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Uniqueness of thermal infrared Intended audience for this information Human vision vs. LWIR spectral comparison LWIR FAQs Clichés of LWIR FLIR-One Particulars Thermal for art using color schemes Thermal for art using contrast Thermal for art when heat is relative Bodies glow in LWIR Thermal human body appearances Emissivity Mirrors in LWIR Low resolution image products The cavity effect Thermal crossover Non Destructive Testing
Art and the human color palette
Using thermal for artistic photography!
Uniqueness of Thermal Infrared
LWIR or Long Wave Infrared (Thermal) is not only practical, it is often so practical it does not get used in artistic endeavors. Most non-practical uses are often video buffoonery. This document may change all that. While near-infrared is known for seeing infrared energy bouncing off of objects thanks to sources like the sun, man-made lights, and other energy sources, the thermal region is somewhat different. Thermal long wave can still see energy reflecting off of things from the sun’s light. However, thermal imagery sees heat that is “emitted”. In other words, heat generated by objects like the human body without needing a light source reflecting off of it. At 3a.m. in a pitch black area the body would still be bright thanks to the emitted energy with no need for any light source. Basically if molecules are moving they will emit thermal. Even ice cubes are not absolute zero in temperature and at the molecular level they will emit as cold in thermal
Aquiline Photography of Colorado Springs, Colorado ©
I personally am drawn to thermal infrared because of its pragmatic, creatively colored, and other-worldly beauty. These slides are for photographers that are interested in something out of this world but also visually factual regarding our surroundings. Thermal images are composed of temperature contrasting objects and are quite artistically compelling. Who else may like LWIR photography?
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Photographers interested in very artsy effects with thermal objects
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People who like an artful & ghost-like glow to people’s appearance
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General folks interested in the thermal infrared and the future of everyday images seeing thermal characters and not just as military targets in thermal viewing. People can appear like comic characters in some thermal instances
It might help to visualize below where thermal infrared occurs in the spectrum‌
A micron is a unit of length equal to one millionth of a meter, used in many technological and scientific fields
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People often talk of all infrared as thermal. There is also near infrared, short wave infrared, and medium wave infrared. Thermal is the long wave known for heat detection called LWIR
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LWIR does NOT see through walls as many conspiracy theorists think. Moreover, LWIR also does not even see through windows because windows emit their own temperature, making them look solid. Thermal cameras can’t use normal glass for lenses because of this and rely on Germanium instead. Thermal can often see through plastics and fabrics
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Night vision and thermal infrared are VERY different. Night vision exaggerates normal light and thermal needs no light at all
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The colors you see in thermal pictures are called “false colors” because the camera takes the temperatures and then assigns its own colors. Users can assign their own colors to the images too
Iron false color scheme
Arctic false color scheme
Glamour models shown in LWIR
Aquiline Photography of Colorado Springs, Colorado Š
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Photographers new to LWIR often think mostly in terms of temperature detection for insulation problems, mold detection, hints of water leaks, and circuit breaker box overloads. LWIR is very good at these functions even when the potential problems are invisible to the human eye
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Colors assigned in thermal images are often white for hot temperatures and darker for cold temperatures. Some adjustments to colors can increase contrast in certain areas of the image. Example is that sometimes image details are clearer if the color palette is inverted
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The reds, oranges, and yellows often represent warmer colors. Cooler temperatures are represented by blues, purple to dark colors. This is all user assigned. Color assignments are to make it easy to relate with
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Once one starts measuring exact numeric temperatures in thermal this is called thermography
Plumbing water leaks Poor insulation detection Locating studs In the wall
Circuit breaker use and overloads detection
Defective electrical outlets
Pragmatic uses of thermal infrared
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Warm hand prints and foot prints stay on surfaces for a considerable time depending on the material. This makes these type of images irresistible to everyone who gets a thermal camera
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Hair blow dryers can make hair glow or surfaces temporarily hot in appearance
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Drinking cold liquids can look fun with drinks making the lips, teeth, and hands cold and dark depending on color scheme chosen. Hot and cold liquids make further dramatic changes in temperature and splash effects when seen in showers, squirt bottles, and water balloons
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One can easily see through rain ponchos or dark black plastic bags if a person or body parts are inside and viewed with thermal infrared. The bag then looks transparent but the bag and outline are visible. The reason some plastic bags are transparent is due to the electro-magnetic frequency. LWIR is a very long wave and therefore passes straight thought the plastic.
Hot water from shower heads makes for dramatic contrast even on the human body
The traditional rainbow color scheme is used in many medical and scientific fields
Fabulous clichĂŠs of thermal infrared
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Forward Looking Infrared company or FLIR has produced the FLIR-One which was initially on an iPhone-5 case that is also a thermal camera. The newer cameras fits other iPhones and Android smart phones too.
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The FLIR One mixes a low resolution regular image with a thermal image. When the FLIR-One’s two cameras do not register the heat side with the conventional image side the thermal and regular image lines are show misaligned
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In the 2007 AQ wanted to do thermal imagery and glamour model photography combined. One challenge was context! Now that a regular camera is sharpening the thermal blobs, one problem is solved. The fact that the thousand dollar thermal camera is below a couple hundred dollars makes the second problem solved. Lastly, having a display, computer processor, email, social media, and even image manipulation tools on the camera itself (because it’s a smartphone) wraps it up into one terrific artistic and technical powerhouse
Getting closer than 3 feet will cause a poor registration between thermal camera and adjacent traditional camera used for contextual outlines in Gen1 FLIR-One
Thermal does not require lights in the studio to Work. However, as shown in the image to the right, with low light the camera cannot show the contextual outlines of the model. The image on the left had studio lights on while shooting.
FLIR-One Particulars
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The FLIR-One (first generation) uses MSX Blending (adds visible camera details to heat images and enhances resolution). This also helps in people photography for context
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The visible camera data is saved or embedded with the thermal image. It remains there even when exported to the camera roll. All of the radiometric or heat number information is still present too. Saving this image with another image program will strip this information away
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Within the FLIR application a swipe between the two images is possible for comparison. One can swipe up or down. The image is low resolution because the program uses a visible camera on the FLIR and not the phone’s built-in quality camera for technical reasons
Low resolution visible-camera information is embedded within the heat image for comparisons
Traditional light must be present for the visible camera to work
Artsy cutaway images can be created in the PC version of FLIR tools+
FLIR-One Particulars
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To begin, perhaps going with color schemes like iron, arctic, or another might be best. The rainbow color schemes associated with thermal infrared have been vastly used in the medical and scientific fields. For this reason some phone applications simply color images rainbow colors and call them thermal. Avoiding cliché might be a good artistic first step
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The edges of the thermal images are usually missing a pixel or two all the way around the frame. Edges can be cleaned up in a digital paint program. Using a clone tool one can fill in missing pixels right next to the problem areas. Alternately one could use the crop tool to get rid of the often thin white border but the image would be undesirably even smaller
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Optionally airbrushing out the hardware’s company logo, placed by default on the image, might be a good idea. In this way the image does not look business but more art oriented
[1] http://www.thefreedictionary.com/thermal+crossover
Studio lights will warm up the background over time, thereby changing the contrast to the model’s temperature
Aquiline Photography of Colorado Springs, Colorado Š
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In standard photography having a good contrast is important unless you are trying to intentionally wash out your subjects. In this way you can position your subject against a colder or warmer background. Actively heating props and other items could intentionally change thermal signatures if desired for an art project
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Studio lights will warm up the background, model, and change the contrast to the scene appearance over the duration of the photo-shoot. For shoots in the northern hemisphere, thermal may be seasonally very different much like near infrared is to trees outdoors
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Showing up to a non-studio location for thermal photography can be unique. Hand and body prints in heat may still be on the surfaces near where one chooses to photograph
[1] http://www.thefreedictionary.com/thermal+crossover
Glamour model in thermal poses wearing a yellow rain poncho
Trash bags, ponchos, and other plastics appear transparent in thermal when heat is inside
Heat residue from foot and hand prints remain long after the person has gone
Aquiline Photography of Colorado Springs, Colorado Š
Liquid levels are visible in a closed & insulated cup
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Heat represented visually is relative. The object’s temperature does not change but the visual does change. Additionally with thermal even the angle of the image can change the perceived look of the heat.
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If one were looking at a chair with something hotter than the chair in the seat cushion, this item in the chair might appear warm. Suddenly one brings their hand into the camera’s view and the ninety something degree heat suddenly makes the chair cushion appear colder and the item in the chair is now less warm than it did before.
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Stated simply, how hot something appears depends on the hottest elements that are in the same scene. The chair seat cushion looks colder because the camera adjusts its temperature scale and range or "auto exposure" like effect.
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This “auto exposure” can be locked in the application settings. But the uncooled VOx microbolometer (sensor) measurements from the FLIR One / Lepton will drift over time and the scenery can drift out of range when locked. This is not a big problem where there is a large temperature range in the image. The clicking sound or shutter on the camera is almost "black body" calibrate where each pixels in the sensor gets the image range put back into position
The mask model’s tongue after eating an ice cube
Car keys on this cloth chair appear warm alone on the chair
Compared to a human hand the keys now appear cooler along with the cloth
Using warmed water in The model sports a this squirt gun we sprayed squirt gun filled with the background. The water cold water In her left In the gun appears warm hand and one filled with but the water on the warm water in her left hand wall now appears cold
Aquiline Photography of Colorado Springs, Colorado Š
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As mentioned, human bodies are seen in thermal infrared in pitch dark with no need for another light source thanks to the body’s emitting energy. All objects give off radiation in the thermal region! The human body gives off enough to look like a flash light in thermal infrared
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Warm skin looks splotchy in thermal close-ups of legs and some arms. This is due to the ability to see limb circulation with the cameras sensitivity to thermal activity
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Coming in from the cold will often show the nose on a person’s face as colder. This makes a dark triangle on the face where the nose appears
Close-up of a Human leg Glamour Model
Glamour Model
The human body’s temperature of 98.6°F provides contrast to cold backgrounds
Aquiline Photography of Colorado Springs, Colorado ©
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Head, neck, and shoulders show some of the hottest and therefore brightest thermal emissions
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Hair, especially when thick is the coldest and darkest on the human body
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Buttocks and breast areas are padded with fat tissue and therefore appears darker than most of the body
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Thighs appear warm but are less bright/warm than much of the body
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The body appearance can be "modified" from the ambient temperature that the body was in before. Imagine having a model do a workout on certain muscle groups. This will make those muscles warmer than the other muscles or body parts due to increased blood flow in the exercised muscles. This can have an interesting effect on the thermal image as one gets more deep details on the body. This is especially interesting on fitness body photos.
Glamour Model
Glamour Model
Body Appearances
Aquiline Photography of Colorado Springs, Colorado Š
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Emissivity is the measure of an object's ability to emit infrared energy. Emitted energy indicates the temperature of the object. Emissivity can have a value from 0 to 1 (0 to 100% where 1 is 100%). Most organic, painted, or oxidized surfaces have emissivity values close to 0.95 or 95%. All objects have an emissivity level! So human bodies are 95% emissive. Mirrors would be 0%.
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All molecules above mind-blowing cold -459 degrees Fahrenheit will emit thermal. That minus four hundred degrees is absolute zero! Anything above this cold level will give off thermal light because the molecules are bouncing against one another [1].
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Much like the standard light we have come to know, reflections also happen. When an object has a very low emissivity such as aluminum foil or a mirror, the heat you see will be not from the mirror but the object’s heat reflected in the mirror. This can be true with windows as well in that what you see is the heat of an object reflected
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Note on Reflection: Some materials have low emission as mentioned so they reflect. However, as they reflect radiation from other objects, they gives a false heat level. In this way if you view shiny aluminum it might look hot but in reality it’s reflecting something hot in the nearby area
[1] http://www.sciencedaily.com/articles/a/absolute_zero.htm
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Mirrors and metallic objects reflect infrared heat. Metal mirrors show the thermal reflection. Plexiglas mirrors often don’t show the thermal signature at all. In this case a camera that overlays the outline from a standard camera can help put context to the object in the image
Mirrors that are non-metallic Will not show the heat in the reflection
This hallway mirror shows the thermal signature of the model
A metallic foil covered gift box reflects thermal profile nicely
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LWIR is normally low resolution compared to mainstream photography cameras. Consider that traditional thermal sensors had to be lowered in temperature first, in order to be colder than the objects being imaged and then the temperature information had to travel through the atmosphere to the camera. This creates an almost noise between the camera and the target
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Most older thermal sensors were a humble 320x200 pixels and cost thousands of dollars. Thermal companies call 640x480 a high resolution! Recently thermal sensors are more common and breakthroughs have been made. Now some sensors do not need liquid cooled. This is driving costs down for consumer markets but their detection ranges are limited
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FLIR One generation-one is a product made for the iPhone-5. Pictures in this publication were created using that hardware. The genius of FLIR-ONE is using a visible light camera to sharpen the low resolution heat information and blow the image up to 640x480 pixels. This enlarges it from the extremely low resolution 80x60 pixels on the sensor. Generation two has 160x120 pixels instead of 80x60
People’s noses often appear colder than the rest of the face in winter (Iron color scheme)
Aquiline Photography of Colorado Springs, Colorado Š
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A cavity or hole can sometimes look like it is generating heat, when in fact, it is not due to the cavity effect. This is no trick as no heat is coming from the cavity, hole, or cave.
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Stated in a more complex way, the cavity effect occurs when energy emitted from a cavity undergoes multiple scattering from internal cavity surfaces, which reduces spectral contrast by increasing the total emissivity. The effective emissivity increases nonlinearly with the number of times the energy is reflected before exiting the cavity [1].
[1] http://www.lpi.usra.edu/science/kirkland/Papers/detectionWebText.pdf Page-3
The cavity effect give the impression this tree is warmer than the surrounding trees. The hollowed out center is quite confusing if one couldn’t see the standard image next to it.
The vehicle with warm tires was driven this day and the other one not driven in more than a day with cold tires. The “cavity effect” gives the impression heat is present under both vehicles
Aquiline Photography of Colorado Springs, Colorado ©
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Not all objects generate heat themselves. Concrete for example can get heated with the sun and slowly cool down as evening sets in. Eventually the sidewalk vanishes in thermal because it is neither hot nor cold in relation to the sensor. This is called “Thermal Crossover”
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Thermal crossover is a natural phenomenon that normally occurs twice daily when temperature conditions are such that there is a loss of contrast between two adjacent objects on thermal infrared imagery. [1]
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For this reason one cannot take just a single image and believe they know everything about a scene. Thermal images taken over time can reveal many more insights into the object’s attributes in temperature and look
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What does this have to do with art? In traditional photography contrast and light are everything. Likewise, in thermal the contrast in temperature will greatly determine the final look of the art or glamour image
[1] http://www.thefreedictionary.com/thermal+crossover
Notice the sidewalk nearly vanishing as its temperature begins matching its surroundings
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Non Destructive Testing (NDT) is basically doing tests on any object without dissecting it or physically disassembling it. All of the forms of light from X-rays to thermal infrared can do NDT. The idea is to evaluate the properties of the material or look at any suspected damage
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Thermography effectively detects different materials or material thicknesses under paint and other coatings. If powerful IR flashes are used to quickly heat the inspection area, different materials under the painting will be heated differently and be visible on the thermography. This will work for detecting corrosion, hidden repairs etc. If the material is thinner, it will be heated quicker and can be seen on the thermography
[1] http://www.thefreedictionary.com/thermal+crossover
Steel corrosion detected with heat gun and thermal camera (2. Gen FLIR Lepton) Image courtesy of photographer Remi Palm
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While doing extensive and novelty glamour image shoots with thermal, the appearance came across like real-time water-color portraits. Maybe it looks more like a comic book super hero style to each person given the garish colors and outlines. What if people didn’t always look like the “human torch” comic character?
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Remi Palm is a photographer and programmer in Vennesla Norway. He created a program merely to change the color palette of thermal images. The idea struck AQ during the process. What if a palette were made to help people in thermal look more like people? The idea was to take all pixels around 98 degrees and make them varying degrees of skin color. From there medium pixels could be given hair color. Lastly backgrounds could be made cold colors since it was winter here in Colorado 2015 and early 2016
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The results were amazing. Not only did it look more artistic but one could plug a whole new person image into the palette and the colors would match up. While it will not be perfect the experiment was a huge success
[1] http://www.thefreedictionary.com/thermal+crossover
The Palette Generator software used to create thermal images with human like skin tones.
Created a scheme for blonde hair and peach skin color
Created a scheme for brunette hair and peach skin color
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Uniqueness of thermal infrared Intended audience for this information Human vision vs. LWIR spectral comparison LWIR FAQs Clichés of LWIR FLIR-One Particulars Thermal for art using color schemes Thermal for art using contrast Thermal for art when heat is relative Bodies glow in LWIR Thermal human body appearances
Emissivity Mirrors in LWIR Low resolution image products The cavity effect Thermal crossover
Non Destructive Testing Art and the human color palette
An artful watercolor look
Hardware Specs FLIR ONE’s Lepton™ thermal sensor is 80x60 pixels and the visible camera is VGA (640x480), but the MSX blending in FLIR ONE embosses the visible camera onto the thermal images, making the resolution appear much higher. When displaying real-time images or recording video, FLIR ONE employs an image enhancement that produces a 160x120 thermal image. When you snap a still image, the thermal resolution is enhanced to 640x480 resolution. What is the operating temperature for the FLIR ONE? FLIR ONE operates at 32°F to 95°F (O°C to 100°C), and has a scene range temperature of 32°F to 212°F (0°C to 100°C). FLIR ONE weighs just 3.9 ounces (110 grams) and with its sleek form factor it adds just 0.85 inches (21.69 mm) of depth and about 0.63 inches (16mm) in length when attached to an iPhone 5 or 5s. Above stats from the website at http://www.flir.com/flirone/press/FLIRONE_Reviewer_Guide.pdf
By Tracy Rose of Aquiline Photography of Colorado Springs, Colorado
AquilinePhotograph@comcast.net
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